1. Field of the Invention
The present invention is directed to automatic transmissions/transaxles used on front wheel drive vehicles and more particularly, to a combination of a lubrication dam and plug for sealing an open space and rear drain opening provided in such transaxles to thereby create a buildup of lubricating oil in the area of the planetary gears and low-intermediate drum and sun gear assembly of the transaxle to thereby reduce metal wear of the planetary gears and allowing additional cooling of the metal components.
2. History of the Related Art
The present invention is particularly designed to alter the lubricating characteristics of automatic transaxles such as the Ford.RTM. Axod.RTM., automatic transaxles of the type utilized on front wheel drive vehicles including the Ford Taurus.RTM., Mercury Sable.RTM., and Lincoln Continental.RTM. during 1986 through 1991 and the electronic version of the transaxle utilized from 1991 to present known as the Ford.RTM. Axod-E.RTM.. Both the Axod.RTM. and the Axod-E.RTM. have the same rear planetary gear arrangement. Lubricating oil is normally introduced into the area between the reverse clutch cylinder and the planet support of the final drive assembly of the transaxle through ports in the sun gear of the shell and gear assembly mounted forwardly of the reverse clutch cylinder. In such transmissions, space is provided between the transaxle casing and the reverse clutch cylinder through which oil may drain forwardly of the transaxle casing through an opening therein into the drain pan mounted beneath the casing. Also, a rear oil drain opening is provided in the casing adjacent the planetary gear assemblies.
It has been noted that excessive heat buildup is created in the planetary gears, causing a breakdown of the gear components, thereby requiring transaxle maintenance.
Applicants have determined, through various testing procedures, that the failure of the planetary gear assemblies can be prevented by increasing the amount of lubricating oil which is retained in the area between the reverse clutch cylinder and the rear planet support of the final drive assembly of the transaxle. In order to modify the lubricating characteristics of the transaxles, it is necessary to make modifications to the interior flow characteristics between the casing and the operating components of the transaxle so as to create a buildup of oil within the area of the transaxle in which the planetary gears may be immersed in an oil bath so as to ensure maximum lubrication of the gears before the oil is allowed to flow back around the rear clutch cylinder and into the oil pan of the transaxle.
In making the tests, it was determined that two modifications are required to the existing transaxle configurations. A first modification is provided to dam the spacing between the lower portion of the reverse clutch cylinder and the transaxle casing, thereby retaining the lubricating oil rearwardly of the reverse clutch cylinder until a substantial buildup of lubricating oil is achieved in the area in which the planetary gears are housed. In addition, the conventional rear drain opening in the casing to the oilpan in the area of the planetary gears must also be plugged so that an increased buildup of lubricating fluid within the area of the planetary gears is achieved.